Earbanger means: An obsequious member of the military who attempts to curry favor with superiors.. It is military jargon and mostly appears in service contexts, war fiction, or among veterans and their families. It is generally derogatory or offensive; worth a quiet word about how it lands on the person being described. If your teen uses it, context will usually make the intent clear. A short, curious question about where they heard it is usually all that is needed to know whether to follow up.